Solid state imaging devices such as a CCD (Charge Coupled Device Image Sensor) and a CMOS (Complementary Metal Oxide Semiconductor) usually have a structure in which light receiving elements are arranged in a lattice shape to make it possible to sequentially read out amounts of charges generated by photoelectric conversion of the light receiving elements. Usually, since these light receiving elements have a single spectral characteristic, an image signal obtained from the solid state imaging device is one channel concerning a color (single color). Therefore, when it is desired to obtain a color image (e.g., a three-channel image of RGB or the like) with one solid state imaging device, a solid state imaging device attached with filters having different spectral characteristics (colors) for the respective light receiving elements is used. An imaging apparatus including such one color solid state imaging device is generally referred to as 1-CCD color imaging apparatus.
Since an image signal for each of the light receiving elements obtained from the 1-CCD color imaging apparatus is information concerning one color, color interpolation processing is performed in order to supplement the information with information concerning the other two colors. However, when linear interpolation performed using color information of peripheral pixels is applied to an image signal obtained from a color solid state imaging device including a Bayer array, which is an array of a color filter in most general use, false colors, which are not colors of a subject, could occur in an image in portions of high-frequency components such as fine patterns and edges.
As a color interpolation method for realizing suppression of false colors, there is an ACPI (Adaptive color plane interpolation) method (see, for example, Japanese Patent No. 3510037). In the ACPI method, for example, when the position of an image of G (green), which is one of three primary colors, is supplemented with information concerning R (red), suppression of false colors is realized by changing information concerning R according to a change in information concerning G.